Brake for road vehicles



March 11 1924.

.J. W. STEWART BRAKE FOR ROAD VEHICLES Filed Feb. 20, 1923 2 Sheets-Sheet 1 JM 594., 2112a,. 2mm):

I March 11 1924. 1,486,611

. J. W. STEWART BRAKE FOR ROAD VEHICLES Filed Feb. 20, 1925 2 Sheets-Sheet 2 I Patented Mar. 11, 1924.

UNITE STATES PATENT OFFICE.

JOHN WALKER; STEWART, F CRAWFORD, SCOTLAND.

BRAKE FOB ROAD. VEHICLES.

' Application filed February 20, 1923. Serial iio. 620,198.

T 0 all whom it may concern: 4

Be it known that I, JOHN WALKER S'rEw- ART, a subject of the King of the United Kingdom of Great Britain and Ireland and residing at' Crawford, Lanarkshire, scotland, have invented a certain new and useful Im rove nent in Brakes for Road Vehicles, o which the following isa specification.

This invention relates to vehicle wheel brakes of the type including a pair or pairs of pivotally connected shoes engageable with a drum.

According to the invention, screws are screw-threaded into the ivotally connected ends of the shoes, each oi which screws pre sents a cup-shaped head for accommodation of a ball joint which functions as a distance piece, the cup-shaped heads .beingformed as toothed crowns engaging a bevel gear on the end of an adjusting rod assing t rough the ball joint and operable om the exterior of the brake housing, the arrangement being such that rotation of the rod effects rotation of the screws in opposite directions, whereby the shoes are either expanded or con-' tracted.

The invention is illustrated in the accomanying di ammatic drawing in which ig. 1 is an e ovation and Fig. 2a plan of a preferred construction. Fig. 3 shows a modification applicable to brakes for Ford cars. Figs. 4 and 5-show arrangements suitable for twin brakes. v

Referring first to Figs. 1 and 2, the brake shown includes a pair of shoes 1, 2 separable by a cam 3 interposed between cain surfaces 4, 5.

The connection between the ends of the shoes remote from the cam surfaces is constituted by a pair of screws 6, 7 in screwthreaded relation with the ends of the brake. shoes. each of which screws 6, 7 presents a cup-shaped head 8 or 9 for accommodation of a ball joint 10 which functions as a distance piece. The cup-shaped heads 8, 9 are formed as toothed crowns engaging a bevel gear 11 formed on the end of an ad ustmg rod 12 passing through the ball oin-t 10. The arrangement is sucli that rotation of the rod 12 effects rotation of the screws 6, 7 in opposite directions, whereby the shoes 1, 2 are either expanded or contracted.

- The modification shown in Fig. 3 is designed for use in a Ford car and isso arranged that the pivotal connection will per- -Witll a r0d'12,

for locking the adjustment rod in selected form the function of the cam 3 in Fig 1. The adjusting rod 12 is replaced by a tube 14 formed atone end with a ball joint 11) and at the other end with means for attachment to the brake-o being fitted within t e tube an adjusting rod 12 provided with a bevel 11 engaging toothed crowns formed on cup-shaped heads 8, 9. For locking the rod 12 to-the tube 14 after adjustment, so that, when the brake operating crank is actuated, the rod 12 and the tube 14 are caused to rotate and the brake shoes are expanded, there is rovided a set pin 15 en aging a screw-thre ed aperture in the tu 14 and entering into lockmg engagement with the rod 12 Fig. 4 shows an arrangement applied to twin brakes where two sets of pivotal conmotions are provided, the respective ball joints being mounted on a single rod 12' correslponding to the rod 12.

n the modification shown in Fig. 5 in which for the rod 12 there is substituted a tube 12 connected to one bevel gear'11 there is fitted within the tube a second adjusting rod 12? connected to the other bevel gear 11. The arrangement shown in Fi 5 pro vides for a justmentof'the twin brakes independently of one another. A set pin 16 en ages a screw-threaded aperture in the tu 12 and enters into locking engagement provision thus being made positions.

I claim 1. In a brake, the combination with a pair of shoes of twoIscrews threaded into ends of the shoes, each screw presenting a cupshalpd h'eatl formed as a toothed crown, a bal {joint accommodated in the.cup-sha ped head an jadjusting rod passing through the balhjiint, and a l bevel gear on the adjusting rod bi gage 'ble with each toothed crown.

2. In a {b ake, the combination with a pair rating crank, there of shoes eadh formed at one end with a camsurface, screws threaded into the other ends ofi the shoes,- said screws presenting cup shaped heads formed as toothed crowns, a ball joint accommodated in said heads, an adjusting member extending through said ball joint, and a bevel gear on said adjusting member engageable with said toothed crowns.

3. In'a brake, incombination, expar ding and contracting shoes having pivots y con-' nected ends, a pair 'of screws in screw- 15 aha v heads having toot-he 24 'qith sgiiticrownst.

threaded relation with said connected ends, said screws presenting cupshaped heads having toothed crowns, a ball joint interposed; between said cuprshaped heads, and 5 an adjusting rod passing through said ball joint and provided with n toothed bevel gear meshing with said totithedvcrowns, said. adjusting rod being rotatable so as torotate said screws. 10

of braking units each comprising two shoes 4. In a brake, in combination, is plurality "having pivdtally connected ends, a pair of :,.--screws in screw-threaded reiation with said connected ends said scsews gir'esenting cupcrowns and a oint inter sed between saiti cupheads gm adjustin means passin E the units, sai

*Ygdjusting means including toothed bevels b shaped -5. Ina brake, in combination, 9. plurality of braking units each comprising two shoes having pivotaiiy connected. ends, a pair of screws in screw-threaded relation with said connected ends, said screws presenting cupsiliffed heads having toothed crowns and n b joint; interposed between sa'ui cupshaped hesids, and adjusting means passin v through the ball joints of the units, said at justing means including independently rotatable toothed .bevelsmeshing with said crowns.

In testimony whereof I have signed'my name to this-specification in the presence of two subscribing witnesses.

JOHN \VALKER STEWART.

Witnesses:

WALLAc-E CRAMTON Fnmwm'rmue, Hm}; Nlcaowon Cum, 

